Under most artificial,
incandescent light,
UV-reactive nail varnish looks just like ordinary clear nail-varnish: the sort you put on to make your
nails slightly stronger and more
glossy. However, go out in
daylight, and the slight
ultraviolet component emitted by
the sun will cause your nails to look slightly purple if you have one coat on. If you have two or more coats, your nails can look blue and
cyanotic under daylight or certain sorts of
fluorescent lighting. Go somewhere with a lot of
ultraviolet light, like a
nightclub, and your nails glow an eerie blue-white. First time I wore this stuff to a
club, I noticed after a while that I'd been spending all the time on the
dance floor moving my hands around and just staring at the strange patterns my
luminous fingernails made. Almost as much fun as
glowsticks.
Increasingly, UV lights are being fitted in public toilets, apparently to make it harder to see your veins to shoot up. Often, I only notice when I walk in and my nails light up in unearthly hues -- a detector of invisible radiation, painted onto the ends of my fingers.
It can be hard to tell whether you've applied UV nailvarnish correctly, or removed it, unless you have a blacklight handy. I didn't check once, and only discovered when I went out clubbing that I had little splashes of the stuff all over my hands, which were covered in huge glowing blotches.